[Lldb-commits] [PATCH] D112697: [lldb] Update field offset/sizes when encountering artificial members such as vtable pointers

[Raphael Isemann via Phabricator via lldb-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGe2ede1715d41: [lldb] Update field offset/sizes when encountering artificial members such as… (authored by teemperor).
Herald added a subscriber: lldb-commits.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D112697/new/

https://reviews.llvm.org/D112697

Files:
  lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
  lldb/test/API/lang/cpp/bitfields/TestCppBitfields.py
  lldb/test/API/lang/cpp/bitfields/main.cpp


Index: lldb/test/API/lang/cpp/bitfields/main.cpp
===================================================================
--- lldb/test/API/lang/cpp/bitfields/main.cpp
+++ lldb/test/API/lang/cpp/bitfields/main.cpp
@@ -97,7 +97,7 @@
 
 struct WithVTableAndUnnamed {
   virtual ~WithVTableAndUnnamed() {}
-  unsigned a : 4;
+  unsigned : 4;
   unsigned b : 4;
   unsigned c : 4;
 };
@@ -146,7 +146,6 @@
   with_vtable.b = 0;
   with_vtable.c = 5;
 
-  with_vtable_and_unnamed.a = 5;
   with_vtable_and_unnamed.b = 0;
   with_vtable_and_unnamed.c = 5;
 
Index: lldb/test/API/lang/cpp/bitfields/TestCppBitfields.py
===================================================================
--- lldb/test/API/lang/cpp/bitfields/TestCppBitfields.py
+++ lldb/test/API/lang/cpp/bitfields/TestCppBitfields.py
@@ -145,8 +145,6 @@
         self.expect_expr("base_with_vtable", result_children=base_with_vtable_children)
         self.expect_var_path("base_with_vtable", children=base_with_vtable_children)
 
-    # FIXME: These all crash due the vtable ptr.
-    @skipIf
     @no_debug_info_test
     def test_bitfield_behind_vtable_ptr(self):
         self.build()
@@ -164,7 +162,7 @@
 
         # Test a class with a vtable ptr and unnamed bitfield directly after.
         with_vtable_and_unnamed_children = [
-            ValueCheck(name="", type="unsigned int:4", value="0"),
+            ValueCheck(name="", type="int:4", value="0"),
             ValueCheck(name="b", type="unsigned int:4", value="0"),
             ValueCheck(name="c", type="unsigned int:4", value="5")
         ]
Index: lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
===================================================================
--- lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
+++ lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp
@@ -2675,11 +2675,6 @@
 
   // FIXME: Remove the workarounds below and make this const.
   MemberAttributes attrs(die, parent_die, module_sp);
-  // Skip artificial members such as vtable pointers.
-  // FIXME: This check should verify that this is indeed an artificial member
-  // we are supposed to ignore.
-  if (attrs.is_artificial)
-    return;
 
   const bool class_is_objc_object_or_interface =
       TypeSystemClang::IsObjCObjectOrInterfaceType(class_clang_type);
@@ -2845,6 +2840,17 @@
     last_field_info.SetIsBitfield(false);
   }
 
+  // Don't turn artificial members such as vtable pointers into real FieldDecls
+  // in our AST. Clang will re-create those articial members and they would
+  // otherwise just overlap in the layout with the FieldDecls we add here.
+  // This needs to be done after updating FieldInfo which keeps track of where
+  // field start/end so we don't later try to fill the the space of this
+  // artificial member with (unnamed bitfield) padding.
+  // FIXME: This check should verify that this is indeed an artificial member
+  // we are supposed to ignore.
+  if (attrs.is_artificial)
+    return;
+
   if (!member_clang_type.IsCompleteType())
     member_clang_type.GetCompleteType();
 


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